1. Field of the Invention
The present invention relates to novel streptovaricin C derivatives and a preparation thereof and antiviral compositions containing the same as an active ingredient.
2. Description of the Prior Arts
Streptovaricin C is antituberclosis antibiotic produced by culturing the strain of Streptomyces 101, species 2494 and has the chemical formula ##STR2## as disclosed in Journal of Antibiotics Vol. 25, Page 71, (1971); Journal of American Chemical Society Vol. 93, Page 6273, (1971) Vol. 93, Page 6275, (1971).
The streptovaricin C is hydrolyzed in a mild oxidizing condition, damavaricin C and atropisodamavaricin Fc can be obtained as disclosed in Journal of Antibiotics Vol. 29, Page 201, (1976) by K. L. Reinhardt.
The inventors have studied on alkaline hydrolyzed products obtained from streptovaricin C have been studied in detail and have found damavaricin Fc together with damavaricin C and atropisodamavaricin Fc.
Atropisodamavaricin Fc is an optical isomer of damavaricin Fc.
In a thin layer silical gel chromatography, they could not be isolated each other to give a single spot.
The inventors have found the optical isomer of damavaricin Fc by a proton NMR spectrum. Damavaricin Fc has P-helicitic structure (natural form) wherein a double bond of C(15)=C(16) is disposed at upper side of carbonyl group C(24)=0 in stereomatic structure to the single bond C(17)-C(18) as that of streptovaricin C whereas atropisodamavaricin Fc has M-helicitic structure (non-natural form) wherein the double bond is stereomatically in opposite position (See the report by Reinhardt and helicity principle disclosed in Angewante Chemie International Ed. Vol. 5, Page 385, (1966) ).